Artificial limb



Dec. 2, 1952 K. C. VESPER ARTIFICIAL LIMB 6 Sheets-Sheet l Filed Sept. 18, 1947 VVENTOR:

Ael- C V65/25e K. c. vEsPER ARTIFICIAL LIMB Dec. 2, 1952 5 Sheets-Sheet 2 Filed Sept. 18, 1947 .rl/ll.

AGENTI Dec. 2, 1952 K, C, VESPER 2,619,652l

ARTIFICIAL LIME Filed sept, 18, 1947 s sheets-sheet s aza /NvE/vroR: KAEL C. VESPEQ AGE/VT.

Dec. 2, 1952 K, c, VESPER 2,619,652

ARTIFICIAL LIMB Filed Sept. 18, 1947 6 Sheets-Sheet 4 I wm /NvENro/e:

570 Khun C'. VESPEQ AGENT.

K. C. VESPER ARTIFICIAL LIMB Dec. 2, 1952 Filed sept. 18, 1947 6 Sheets-Sheet 5 Dec. 2, 1952 K. c. vEsPER 2,619,652

ARTIFICIAL LIMB Filed sept. 18, 1947 e sheets-sheet 6 WE/Vroni KAQL C. V55/25,2

- AGL-N72 Patented Dec- 2, 1952 UNITED STATES PATENT OFFICEy ARTIFICIAL LIMB Karl C. Vesper, Los Angeles, Calif., assigner to A. J. Hosmer Corporation, a corporation of California 27 Claims.

My invention relates to improvements in articial limbs, and more particularly to improved kneeebrake mechanisms and controls therefor.

In many artificial legs the upper limb member and the lower limb member are pivotally connected by a knee-joint. Such a knee-joint acts asa hinge to permit the legs to bend or ex, and to extend or straighten. In artificial legs which are designed to simulate the action of the natural legs they replace, it is highly desirable to employ a knee-brake, or knee-lock, mechanism which prevents flection of the knee-joint under a wide variety of conditions Without, however, interfering With the extension of the knee-joint. Such a knee-brake mechanism serves to protect its user from many falls caused by involuntary kneebuckling; but stillprovides him with a great deal offreedom of'movement.

One of the principal objects of my invention is to provide an artificial leg with an improved kneebrake mechanism Which serves to prevent involuntary buckling of the knee-joint under a wide variety of conditions.

Another object of my invention is to provide a knee-brake mechanism which responds to involuntary flection of the ball-joint of the foot of the artificial leg. A more particular object is to provide an artificial leg having a ball-joint and employing a toe control unit, to actuate a kneebrake mechanism with means for adjusting the point of inception of operation of the control unit accordingl to the degree of lection of the balljoint. A still more particular object is to provide an artificial leg employing a toe control unit for actuating a knee-brake mechanism with means for adjusting the point of inception of operation of the control unit by means of an adjustment device located on the upper leg member and While the articial leg is in use. A still further object is to provide a toe control unit which automatically seats itself in a position corresponding to a minimum degree of ball-joint lection in the event of failure of 'the means for adjusting the point of inception of operation. And still a further object is to provide an artificial leg with a toe control unit which is hydraulically adjusted from a position on an upper legV member for setting the point of inception of operation. vAnd `a still further object is-to provide an adjustment device by meansof which the point of inception of operation may be adjustably set at any one of a series of selected positions while the artificial leg is in use.

Another object of my invention-is to provide an artiiicial` leg with a knee-brake mechanism heel pressure.

which responds to pressure on the heel. A more particular object is to provide an articial leg employing a heel control unit for operatingv a knee-brake mechanism with, means for adjusting the point of` inception ofv `operation thereof vacccrding to the amountof pressure applied' to the heel.

Another object of my invention is to provide an articial leg with a knee-brake mechanism which responds either to ball-joint flection or to A further object is to provide an articial leg employing a hydraulic knee-brake mechanism with mechanical control units respectivelyresponsive to actuate the knee-brake mechanism in accordance With ball-joint flection and heelr pressure. Ay still further object is to provide such an artificial leg With hydraulicv control unitswhich are respectively responsive to balljoint ection and heel pressure. And still a further object is to provide such an artificial leg with electrical control" units which are respectively responsiveV to ball-joint flection and heel pressure.

Another object of my invention is tofprovide an articial leg with an upper leg member and a knee-brake mechanism Which are adapted for use on a leg Which is amputated below the knee.

Another o-bject of my invention is to provide an articial leg with a knee-brake mechanism which can be voluntarilyy released duri-ng operationv in order to permit knee ection. A still further Vobject is to providev an artificial leg employing a knee-brake mechanism with a control device Which can beY voluntarily operated to render the knee-brake mechanism operative'to lock'V the knee against ection, and Which then effectively releases the braking mechanism to any selected-degree so as to control the rate of knee flection as desired. And still a further object is to provide such a-control device which is manually operative from the hip position ofthe upper leg member while the artificial leg is in use.

Another object ormy invention is to provide an articial foot with a control unit which is adapted` to actuate a knee-brake mechanism. A further object is to provide an articulated articial foot with a control unit which is responsive to ball-joint ection. A still further object of my invention is to provide an yarticial foot employing a toe control unit with means for adjusting the point of inception of operation thereof according to the degree of ball-joint flection.

Another object of my invention' is to provide an artificial footwith acontrol unit which isresponsive' to heel pressure. A still further object 3 is to provide an artiiicial foot employing a heel control unit with means for adjusting the point of inception of operation thereof according to the amount of pressure applied to the heel.

Another object of my invention is to provide an articulated artiiicial foot employing a balljoint control unit and a heel control unit with common means for communicating a control force to a remote point.

Another object of my invention is to provide an articulated artificial foot with an improved ball-joint that is rugged and not subject to side sway. Y

Another object of my invention is to provide an improved knee-brake mechanism employing a brake-piston operating in a cylinder, and a check valve mechanism arranged in a passageway communicating with spaces within the cylinder on opposite sides of the piston. A further object of my invention is to provide a hydraulic knee-brake mechanism with a Vcheck valve mechanism which employs a valve head which floats resiliently therein, and which is movable between a withdrawn position in which liquid is free to flow in.

either direction therethrough and an operative position in which liquid is free to iiow therethrough in only one direction. A further object is to provide a hydraulic knee-brake mechanism employing a brake-piston operating in a cylinder with two passageways each communicating with the spaces in the cylinder on opposite sides of the piston, and a check valve in one of the passageways which may be rendered operative to limit the flow therethrough to one direction and a throttle valve in the other passageway which may be adjusted to control the rate of flow therethrough in the opposite direction in by-passing relationship to the check valve. A still further object of my invention is to provide such a hydraulicr knee-brake mechanism with common means for sequentially rendering thecheck valve operative and for adjusting the opening of the throttle valve.

' There are many other objects of my invention fwhich together with the foregoing objects and there are many advantages of my invention will be readily apparent from a consideration of the several embodiments thereof` which are illustrated in the accompanying drawings and described below. Various features of these embodiments of the invention operate on mechanical, hydraulic, andelectrical principles. While the various embodiments of the invention operating on such principles are herein illustrated and described in detail, it is to be understood that many forms of the invention, some of which might even incorporate detailed improvements to be discovered in the future, will occur to those skilled in the art without departing from the main principles underlying my invention. It is, therefore, to be understood that my invention is not to be limited in any of its features to the details of the embodiments illustrated and described herein, but that reference is to be made to the appended claims fr-a determination of the limits of my invention.

In the drawings, wherein the same numbers refer to like parts in the several views,

Fig. 1 is a side elevational View of an articial leg embodying features of my invention and employing mechanical toe control and heel control units;

Fig. 1a is a fragmentary side elevational view illustrating an improved knee structure;

Fig. 2 is an elevational view of the artiiicial foot 4 and ankle of Fig. 1 with the ball-joint flexed a maximum amount;

Fig. 3 is a vertical sectional View illustrating details of the artificial foot and the ankle joint of the articial leg 0f Fig. 1;

Fig. 4 is a fragmentary detail view shown in vertical section of the artificial foot of Fig. 3 illustrating the operation of the toe control unit;

Fig. 5 is a fragmentary view illustrating a mechanical arrangement for communicating a control force from the artiiicial foot of Fig. 2 to the knee-brake unit;

Fig. 6 is a rear elevational view of the artificial legof Fig. l, partly in vertical section, illustrating the connection of the hydraulic brake unit between the upper and the lower leg members;

Fig. 7 is a vertical sectional view of the hydraulic brake unit employed in the artificial leg of Fig. Y1 takenon the plane 'l-l of Fig. 6;

Fig. 8 is a vertical sectional View of the ankle joint and artificial foot taken on the plane 8 8 of Fig. `3;

Fig. 9 is a detailed View taken on the line 9-9 of Fig. 6;

Fig. 10 is an enlarged fragmentary view of a knee-joint hinge;

Fig. 1l is a side elevational View of another artificial leg also embodying features of my invention and employing hydraulic toe control and heel control units;

Fig. 12 is a vertical sectional view illustrating details of the artificial foot and the ankle joint of the artificial leg of Fig. 11; o

Fig. 12a is an enlarged Vertical sectional view of the hydraulic heel control unit;

Fig. 13 is a fragmentary plan View of the toe control unit of the artificial leg of Fig. l1;

Fig. 14 (on Sheet 6) is a detailed vertical sectional view showing the linkage of the device used for adjusting the toe control unit of the artificial leg of Fig. 11;

Fig. 15 is a detailed Vertical section-al View of the control device;

Fig. 16 is a vertical sectional view of a part of the toe control unit of the artificial leg of Fig. l1;

Fig. 17 is a side elevational View, partly in vertical section, of a modified hydraulic brake unit, for use in an artificial leg;

Fig. 18 is a detailed fragmentary View, partly in horizontal section, of the throttle valve mechanism taken on the line |8-I8 of Fig. 17;

Fig. 19 is a detailed fragmentary View of the throttle valve operating linkage taken on the line IS-IS of Fig. 17;

Fig. 20 is an elevational view partly broken away of a device adapted for adjusting the toe control unit of the artificial foot of Fig. 21 and for controlling the hydraulic brake unit of Fig. 17;

Fig. 21 is an elevational View of an alternative form of artificial foot for use in an artificial leg;

Fig. 22 is a vertical sectional view of the articial foot of Fig. 21;

Fig. 23 is a vertical sectional view of the toe control unit of the artificial foot of Fig. 21 taken on the line 23--23 of Fig. 24;

Fig. 24 is a plan view of the toe control unit of the artificial foot of Fig. 2l;

Fig. 25 is a side elevational schematic view of another artificial leg also embodying features of my invention and employing electrical toe control and heel control units;

Fig. 26 is a fragmentary Vertical sectional view of part of the toe control unit of Fig. 25;

Fig. 27 is a fragmentary vertical sectional view of parini' the heel control unit of Fig. 25 andV sapiente Fi'g; ZBis anenlarged fra'gmentaryfview in' ver- :tical section, showing details of the electromagneticrslaveun'it .of Fig. 127.

I. General construction of artificial Zeg An artificial leg ofthe typeto which my invention is particularly lapplicable is illustrated in Figs. 1, 2, 3, 6 and 8. This artificial leg is completelyarticulated and comprises a lower limb or/leg member 3l]v pivotally attached to an upperr limb or lleg member l32 by means of a knee joint 314and also comprises a foot member 36 pivotally attachedto thelower leg member 30 by means of 'an ankle joint 38. The foot member 36 itself comprises 'a .main foot section 4B and a toe section 42 'pivotally attached thereto by means of a ball'r joint 44. The. knee joint 34, the ankle joint '38, and the ball joint 44 are designed to pivot "about substantially horizontal transverse axes. The upper leg member 32 is in the form of a socket which is adapted to fit over the stump of an above-the-knee amputated leg. The upper leg member 32 may be rmly secured in place on the amputated legby any suitable meanssuch as a belt or harness (not shown). If desired to adapt the artificial leg to a below-the-knee amputated leg, a rearwardly protruding pocket 46 as shown in Fig. 1a,.may be vprovided at the lower vrear portion of the upper leg member 32. In any event, a suitably cushioned liner 48 that ts the amputated leg snugly is used to support the amputated leg and hold its lowermost extremity spaced above the bottom open end 5B (see Fig. 6) ofthe upper leg member 32.

The knee joint includes a pair of upper hinge straps 52. suitably secured to the outer wall of the upper leg member 32 and also a pair of forked lower hinge straps 54 likewise suitably secured to the outer surface of the lower leg member 3i). As shown in Figs. 6 and 10, the adjacent ends of the hinge. straps on opposite sides of the knee are secured together by machine screws 5@ and are arranged to rotate on roller bearings 60 to permit free pivotal movement at the knee joint. The straps 52 and 54 are provided with front stops 62 which abut when the upper and lower legimembers 30 fand 3.2 are extended into their .aligned or. straight position. They are also providedwith'rear stops S4 so as torlimit the iiection off'the knee joint to an angle of vabout 50 'The lower leg member 30- is of hollow tubular Vconstruction shaped in the form of a natural lower leg, in order to provide a cavity in which thesmain working parts of a knee brake mechanism .maybe mounted as hereinafter explained. Ashank piece 66 isitted securely within the shin portion. at. the lower. end of the lower leg member 3.0 and is providedw-ith a pair of depending bearings GBIin'Whichk an ankle axle it .issupportec as shownin Figs. 3 and 8.

The' main foot section 4%! is provided with a recess, 'l2 having side walls 'i4 which enclosev the bearings 68. and the ankle 'axle l2. A supporting bracket-16 ismounted in the bottom of this recess and is provided with two semi-circular weight-bearing yokesv 13. upon which the ankle axlerests. rThel eye 19 of. a hollow eye-bolt 8B, locked -bymeans of a nut '32 tothe mainfoot sectionV 40, encloses the ankle axle 1B and serves to secure the lower leg member 30 and theV foot member 36 together and to form a pivot at the ankle joint 38. Front and rear ankle bumpers 84 and 86 composed of resilient material, such as rubber, are rmly held iniplac'e betweenrthet` lower wall 88 4ofthe-shank piece Bl'and thebase '9010i .6 the recess. 12. The bumpers `84 andare normallyv 'under slight compression 'and `serve to restoreftheankle joint 38 to' itsl normal. configuration. when flexed. rearwardly therefrom by stepping. down on the heel portion. 92 of the foot member 36or. when flexed forward therefrom by stepping'down on vthe ball joint. 44 or thetoe section 42 of'the foot member.

Theball joint 44 is formed by means of a flexible plate 94 and an overload bumper 96 attached thereto between adjacent faces of the main foot section 4G and the toe section 42. A resilient sole piece SB underlies the bottom of the foot member 38 from the toe |20 to the arch |92. Likewise, a resilient heel piece |04 is secured to the lower side of vthe heel portion 92. The plate 94, the overload bumper 96, the sole piece Q8, and the heel piece |64 may be formed from any suitable resilient material such as a rubber composition. It is to be noted that when the user of the artificial leg steps down on the toe section 42 or shifts his weight from the heel portion 92 to the toe section 42, the ball joint 44 fiexes.

According to myA invention, an improved knee brake mechanism is provided which locks the knee joint against any further flection whenever the ball joint flexes more than a predetermined amount, and also locks the knee joint against further ection whenever upward pressure exceeding a predetermined amount is applied to the heel portion. Preferably, the knee brake mechanism comprises a brake device which includes a pairv of cooperating brake members respectively connected to the upper and lower leg members and a toe control unit and a heel control unit which respond to predetermined action of the foot member to render the brake device operative to resist further flection of the knee joint without, however, interfering with extension of the knee joint.

II. Hydraulic brake unit A knee brake mechanism of ther type which I prefer to employ in my invention comprises a hydraulic brake unit l I0 which is located within the lower leg member 3G as indicated in Figs. 1 and 6. The brake unit d includes a body member ||2 pivotally attached to the lower end of a pair of downwardly depending support brackets ||4 firmly secured at their upper ends to the lower hinge straps 54. As illustrated in detail in Fig. '7, this body member M2 comprises a main elongated cylinder I6 closed at its ends by means of upper and lower threaded plugs H3 and |25. A double-acting piston |22 is slidably arranged within the cylinder Ilia` and is rigidly secured to a lower piston rod |24 which extends through the lower plug |2|l andan upper piston rod |26 which extendsA through the upper plug.' I3. v

The lower plug |22 is provided with a downwardly projecting. nipple or plug extension |28 which isthreaded at its end. A bearing member I3@ is.. loosely held on. the plug extension |28 by means of a nut |32 and is provided with two oppositely extending pins |34 which are seated in needle bearings |36 at the lower ends of the brackets ||4.

As shown in Figs. l and 6, the upper piston rod |25" is attached by means or a loose fitting bolt and clevis 33 to a downwardly extending arm Hill at the bottom of a knee yoke |42 which is pivotally attached to downwardly inclined, rearwardly extending. arms. |44 on the upper hinge straps5'2. These arms |44 preferably `extend inwar'dly through .side openings |4t` in `the sides. of

the upper leg member 32, the yoke |42 being held within the upper leg member and extending downwardly through the bottom opening 50 therein. The use of such a yoke is particularly convenient when adapting the artificial leg to a below-the-knee -amputated leg as it provides a space within which the knee is easily supported. The bolt and clevis |38 pivot about a forwardly extending axis so as to provide for small transverse sway between the upper and lower leg members 30 and 32 without bending the hydraulic brake unit I0.

'I'he spaces |48 and |50 above and below the piston |22 communicate by means of upper and lower ports |52 and |54 respectively with an internal passage |58 which passes through a check valve |58, as shown in Fig. 7. It will be noted that the inner ends of the plugs I I8 and |26 are chamfered in order to provide free access of the ports |52 and |54 to the spaces |48 and |58 on opposite sides of the piston |22.

The check valve |58 includes a body section |68 formed integrally with the body member ||2 and includes a cylindrical chamber |82 which forms part of the passage |56 and thus communicates through the upper port |52 with the upper space |48 and through the lower port |54 with the lower space |58. A valve seat |84 is formed in the chamber |82 by means of a ring |66 which is press-lit therein. A head |88 lof a valve |68 is arranged in the lower portion of the chamber |62 in working relationship with the valve seat |84. The valve |89 is provided with a downwardly directed extension |10 which is slidably arranged in a bore |12 which passes through the body section |80 coaxially with the chamber |62 and is piloted thereby t0 form a rm seal between the valve head |88 and the entire periphery of the valve seat |84 when the valve |88 is in its uppermost position. An operating member |14 which serves, in eiect, as a valve rod is arranged in a counterbore |16 at the lower end of the bore |12.

The valve |88 is recessed at its upper and lower ends in order to receive compression springs |11 and |18 between which it is iioated. The upper end of the upper compression spring |11 fits within a bore |19 inl a threaded plug |88 which closes the upper end of the check valve chamber |82 and the lower end of this spring ts in the recess |82 at the upper end of the valve head |88. The lower end of the lower compression spring |18 nts within a tubular portion |84 of the operating member |14 which is slidably arranged in the lower end of the bore |12 and the upper end of this spring fits in the recess |86 at the bottom of the valve extension |18. The operating member |14 is provided with a flange |88 which slides in the counterbore |16 between a shoulder |89 at the inner end thereof and a stop ring |98 which is clamped in an annular groove |9| within the counterbore. The relative strengths of the two compression springs |11 and |18 are so chosen that the valve head |68 remains in a retracted or Withdrawn position from the valve seat |64 when the operating member |14 is in its lowermost position with the flange |88 against the stop ring |88, and the valve head |88 operatively engages the valve seat |84 to act as a check valve when the operating member |14 is in its uppermost position with the flange |98 engaging the shoulder |88. The threaded plug |80 is preferably provided with a square head |92 by means of which the plug may be adjusted inwardly and outwardly of the check valve body section |60. This ad- .justment serves to vary the setting of the retracted position of the valve head |68, so'that the rate at which fluid may flow downwardly through the check valve |58 is varied. The resultant variable throttling or restriction of ilow permits adjustment of the rate of knee joint extension, thereby eliminating the need for a friction element in the knee joint.

The spaces in the brake cylinder I6, the check valve chamber |62, and the intercommunicating passages therebetween are substantially iilled with a liquid, preferably an oil having a low temperature coefficient of expansion. Suitable packing and seals are provided in all the hydraulic devices to prevent seepage of oil from such spaces or the leakage of air thereinto. In addition, an O-ring |83 is arranged in an annular groove |94 in the piston to prevent leakage of oil past the piston between the spaces |48 and I5 on opposite sides thereof. A small amount of air is left therein to accommodate volumetric changes due to movement of the valve |88 into and out of the chamber |62.

When the check valve |58 is inoperative, that is, when the valve head |68 is withdrawn from the valve seat |84, the liquid is free to be pumped by the piston |22 in either direction past the check valve as the knee joint 34 is liexed and straightened. But when the check valve |58 is operative, that is, when the valve head |68 is pressed against the valve seat |64, the flow of liquid in an upward direction through the check valve is blocked but liquid can flow therethrough in a downward direction. Thus, when the check valve |58 is operative downward, movement of the piston |22 within the cylinder |65 corresponding to flection of the knee joint 34 is prevented. The additional upward pressure of the valve head |88 resulting from flection serves to seat the valve head more rmly on the valve seat |64. However, when the check valve |58 is operative, it does not interfere with upward movement of the piston |22 in the cylinder ||6 corresponding to extension of the knee joint 34.

III. Mechanical control units According to my invention the check valve is rendered operative in response to predetermined movement of a part of lthe artificial leg in order to lock the knee joint against further lection, whenever that predetermined movement occurs. A slave device is provided on the lower portion of the body member in order to force the operating member upward whenever this predetermined movement occurs. In the form of the invention illustrated in Figs. 1 to 10 inclusive, the actuation of the hydraulic brake unit is accomplished entirely mechanically, that is, the toe control unit, the heel control unit, and the slave device are all of mechanical construction.

As shown in detail in Fig. 7, the slave device 208 of this articial leg includes an actuator rod 202 which is slidably arranged in a pilot sleeve 204 in a solid branch arm 206 of an apertured cup-like supporting member 208 which is held on the nipple |28 directly above the bearing member |30. A slot (not shown) on one side of the supporting member 208 fits snugly over the protruding portion 2|0 of the body member in which the external passage |56 is formed, in order to maintain the actuator rod 202 registered in vertical alignment with the valve rod |14.

The control unit 2| 2 comprises two cooperating actuating members 2| 4 and 2|6 mounted respectively on the. toe section 42 and the. main HiB-159265@ foccsecnon- 4o, as illustrated particularly mV Fig. v3; The actuating members 212 and 214.` areV arranged to cooperate in the actuation of the'v hydraulic brake unit: 110 when the ball joint 44Y is flexed. more than a predetermined amount. More particularly, in the embtndirnentrof. the toe control unit 212 illustrated in detail' inv Fig. 3, one of the actuating` members-comprises a toe bumper. 214k which is adjustably positioned on the rear face 218 fof the toev section` 42. This member 21'4comprisesy a narrow rubber block 219l having a width of about of an inch, covered at its rear and frontl ends by means of iiexible metal cover segments 220 and 222-. The entire bumper 214 is arranged to be compressed and to expand longitudinally in a narrow vertical groove 223 cut in the upper side-22-4-and the rear face 218 of the toe section 42. The adjustment ofthe position of the bumper 2.14 isfaccomplished by means of a screw 225 which is attached to the front cover segment 222 and which passes through av bore 226 extending to the toe |00.

The screw 225v engages a threaded insert' 228r which ts within a transverse recess 230 in the' upper side 224 `o1l the toe section 42. With' this arrangement, to adjust the toe bumper 214 in position backward or forward in the toe vsection 42, it is only necessary to' inserta screw driver into' 'the forward'en'd of the bore 226 and turn the' screw 225 in the desired' direction.

The" otherl actuating memberV 216 of the'` toe control unit 212 comprises ato'e rod 23 which is arranged' tobe movedV forward and backward in a longitudinal' bore 232 which extends from the front face' 234 of the main foot section 46 to a point adjacent the heel portion' 92. An' elongated tubular cap 236 is press-:lit over the forward end of the toe rod 231V and is arranged to slide within' a' pilot sleeve 238 which isl presst within the frontend of the bore 232. The sleeve 238 is ared inwardly at its inner' end 239' and a compression spring 2'40 is arranged' within the sleeve between the cap 236 andV this flaring end, in order' to urge the toe rod 231 forwardly into a position opposite the` bumper 2'1'4.. The rear end of the toe rod 231 slides within a guide 242 adjacent the heel, this guide being provided with a vertical slot 244m which the rear end 245 of the toe rody maybe moved vertically for purposes to be explained hereinafter. vThe rguide 2:42 is held firmlyY in place by means'of a bolt 246 which also serves to hold 231 at a. point slightly forward of the push rodl 24B' andthe sides of the rear end 245 of-the toe rod 231 are iiattened so that when it is forced4 rearwardly by the toe bumper 2 14, the cam 254 forces the push rod 248v upwardly.

A cup-shaped socket 256 screwed-lintothefupper end'of the main-push rod-248v serves to support thelowermost end of anfauxiliarypush rod 258A which is pivotally attached to the lowermost end of the actuator rod 202 by means'of a loosetting tubular connector, 260vand` a: Cotter: pin

262, as indicatedin-Figi` 5; The lowermost: end

of the auxiliary push rod: 258 is:y capped. bys ai rounded tip-piece- 264` which. ii-tstcloseiy,v but not; tightly within the socket 256. A compression. spring 266 arranged. between,` the connector 2.60V and the, pilot sleeveY 204'v serves to' maintainv thel tip-piecev 264 in positive engagement with the socket 256.

With this a`rr`anger'nentA when vthewball joint 441 isre'xed more than-a predetermined amount, the bumper 214 pushes then toel rod -231l rear-- wardlyagainst the force of the compressiorlfsprin'g-l 240'. Asia result the cam 254 forces-'the push rod 248 and the/auxiliary push rod 258- 11pward-A against the force' of thev springs' 252 and 266, thereby forcing the actuator rod 202 intoengagementy withr the valve rod ['14, forcing the valve head 1.68 upward agafinstthek valve seat 164, thereby'- renderingvth'e check valveA -1-58'-operative. Wheny the balljoint4 44 is extended orv straightened, the compression" spring 240 forces the toe rod' 231- forwardly, withdrawing the camv 254 from the main push rod 248 so that the springs'2-52l and 266 force the main' push rod 248 and thev auxiliaryl push rod-,258 downwardly, thus causing thevalve'rody 1'14 to be drawn downwardly withdrawing the valve'head- 168V from the-` The heel control unitl 261 illustratedinv Fig.A 3y comprises a heel; lever 268- whichi isf pivotally at`VA tached at the arch portion 162 ofthe main-footA section` 40 at 210 for pivotal movement about ai transverse horizontal axis. The heellever 268 extends'rearwardly' from the p'ivotj point; eindtermina'tes" in a downwardly projectingV finger 272- substantiallyush with'the bottomsurface oft-he resilient heel piece- 101|' so that it may beforced upwardly when an upward pressure exceeding ai predetermined amount is applied tofV the heelipor-A tion 92. An upwardly projected finger 214 is4k formed in the heel'v levefr` 268 intermediate its? endsV anddirectly beneath the head 25.0 o`fthe main push" rod 248 and incontact with the'lower side of the toe rod 23|.

With this arrangement when an upward pres'- sure exceeding a predeterminedv amountA is applied to thel heel portion 92v as when theI user of the artificial leg steps" down on-the hee'lfportion, the main push rod 248 and' the. auxiliary push rodV 258 are forced upwardly, thereby rendering theY check valve 158 operati-v, andfwheny the'pressurelon theA heel portion is released; the main push rod and-the auxiliary pushv rodV are forced downwardly in thel manner previously explained, thereby rendering the check valve inoperative. As the heel lever r268 is forced upward, the toe rod 231 bends anditrear end 245 slides upward inthe slot 244 and when the heel lever is-released, the toe rod straightens and its rearend returns/to its former position in thev bottomfof the slot.

From the foregoing, itV isreadily seen that the check valve-is rendered-operativeV upon actuation of either' the toecontrol unitI or the heel control unit'. In either event-,the knee` joint 34-isA locked against further flection-in whateve'rfpo'sitionv it then finds itself without, however-,1 interfering with anyextension thereof;

1v. opration of artificial zeg with mechanical; controlV unit Consider now theoperation. of this articial `leg commencing from al standing position, andassumef by way ofexample thatthev artificialleg.- is-the users right' leg and` that; his left leg-.11s.

11 I natural. In the normal standing position the ball joint is straight and there is little, if any, pressure on the heel portion. In this condition, :duid is free to pass in either direction through the check valve, but since the leg is straight it is actually only prepared for fiection of the knee joint.

If, for any reason, while in the standing position, the user should commence to fall forward while the foot member is on the ground, both the knee joint and the ball joint commence to fiex.- With the knee brake mechanism of the present invention, however, as soon as the ball joint lexes more than a predetermined amount, the toe control unit renders the check valve operative, thus preventing upward flow of liquid therethrough and locking the knee joint against any further fiection. This locking of the knee joint prevents collapse of the artificial leg and, breaks the users fall. With his artificial leg in this condition, even though further flection of the knee joint is blocked, the user may raise himself, causing the artificial leg to straighten, by virtue of the fact that the fiowfof uid past the check-valve in a direction corresponding to knee joint extension is permitted.

,If, while in the standing position, the user starts to walk forward, commencing with his left foot, his weight is first shifted to his artificial leg and as he moves forward both the knee joint andthe ball -joint of the articial leg flex. As before, when the ball joint is flexed more than a predetermined amount, the knee joint is locked against flection, thus preventing the artificial leg from collapsing. While the knee joint is so locked, the user may continue the forward advance of his natural leg without danger of buckling of the artificial leg. When the left foot strikes the ground, the users weight is shifted thereto and he raises his artificial leg, throwing it forward and straightening the knee as he does so by the inertial effect of the forward movement. As he places the artificial leg downward on the ground, he shifts his weight to the heel portion of the artificial leg, rendering the checkvalve operative and thus locking the knee joint against flection. With his weight on the heel portion of his artificial leg, the user liftsV his left leg and steps forward. As his body is carried forward, Yhe shifts his weight from the heel portion and then to the toe portion. As his weight is so shifted, the knee joint is eXed slightly and then the ball joint flexed in the manner explained above and he is able to continue the alternating operation of the natural leg and the artificial leg, closely simulating walking with two natural legs.

While in the standing position, if desired, the user may shift his weight to the heel portion of the artificial foot member, thus locking the hydraulic unit against knee joint iiection, and step backward with his left leg.

In order to seat himself, the user of this artificial leg shifts the weight of the artificial leg tothe ball joint without fiexing the ball joint and ne fieXes his artificial knee joint as he lowers himself, carrying most of his weight on hisV left leg. In order to rise from a sitting to a standing position, the user, as a safety precaution, shifts his weight to the heel portion of his artificial leg and straightens the knee joint of the artificial leg as he uses his left leg in rising.

In order to climb stairs, the user shifts his weight to the heel portion or the toe section of his artificial leg, locking the knee joint against flection while he advances the left foot, exing the natural leg. In this operation the' artificial leg supports him while he carries himself'forward to place the left foot on the next higher step. He then raises the foot of his articial leg to this step by bringing it forward and straightening the natural leg at the same time. He then advances his left leg as before described and repeats the action as he progresses up the stairs.

To descend stairs, the artificial leg is periodically advanced to the next lower stair as the natural leg is flexed. The users weight is then shifted to the heel portion of the artificial leg and the left foot is moved to the same stair. In this operation, as Vthe articial leg is lowered to the next forward stair, the weight of the user is supported by the left leg while this leg is flexed, and the artificial leg is then held straight by means of pressure applied to the heel portion of the artificial leg as the left leg is advanced.

V. Hydraulic control units ln the embodiment of my invention illustrated in Figs. 11 to 17 inclusive, a toe control unit, a heel control unit, and an intermediate or slave device of the hydraulic type are employed to actuate the hydraulic brake mechanism in response to predetermined ball joint iiection and a heel pressure. This embodiment of the invention also includes provision for adjusting thetoe control unit during use to vary the point of inception of 'operation of the toe control unit according to the requirements of the user.Y

The slave device 289, which is substituted for the slave device 299 of Fig. 7, comprises a slave cylinder 282 formed unitary with the body member H2 of the hydraulic brake unit H0. Such a slave device 239 is illustrated in detail in Fig. 17. More particularly, the actuator rod 284 in this case is attached to a piston 289 which is slidably arranged within the slave cylinder 282. The piston 286 is normally forced downwardly into its lowermost position by means of a compression spring 281. The Working chamber 288 Within the slave cylinder 282 communicates with the toe control unit and the heel control unit by means of flexible tubing 289 having two branches 290 and 29| composed, for example, cf a resilientv portion 36. An inner cylinder 298 is slidably arranged within the primary cylinder and a piston 390 connected to a toe rod 3D2 is slidably arranged within the inner cylinder. The inner Y cylinder 298 acts as a master cylinder with re- .ber 304.

spect to the slave cylinder 282, as more fully explained hereinbelow. More particularly, as illustrated in Fig. 16, the outer cylinder 298 comprises a body member 394 which is Vclosed at its lowermost end by a threaded cap 306'and the chamber 398 formed within this cylinder communicates by means of Va passage 3H] with Ya hydraulic control line or con-duit 3l'2. The inner cylinder 298 comprises a body member 3 I4 having a cylindrical head 3dS extending through the cap'396 anda tubular tailpiece 320 threadably secured to the opposite end ofthebody member S14-and extending through the other body mem- The tailpiece'329 is connected to the lowermost end of the conduit branch 299 to provide communication between the chamber 32| in the master cylinder 298 and the chamber 2188 v in the slave cylinder 282. `The head 3I6 and the 1i3` andthe; body member 304 in order to guide the inner cylinder 238 within the primary cylinder 296. A fiangeor collar 322 formed on the outer surfaceof the body 3|4 of the secondary cylinder 298 slidably engages the wall of the primary cylinder 296 and acts as a piston therein. A compression spring 324 arranged between the ange 322 and the cap 336 normally' urges the inner cylinder 288 inwardlyin ther outer cylinder 296v against the pressure of any hydraulic iiuid contained in the outer cylinder chamber 308.

The control line 3|2 leads upward through a hole 324 in the outer side of the lower leg. member 30 to an adjustment device 326 which is mounted at the hip position on the upper leg member 32. The adjustment device 326 cornprises a control cylinder 328 in which a control piston 330 may be adjustably positioned by means of a manually adjustable knob 332 connected thereto through a suitable linkage 334, as illustrated, for example, in Fig. 14. A stop mechanism including a ball 336 and spring 338 mounted on 'the housingl 333 oi the adjusting device 326 cooperate with recesses 340 on the inner side of the knob 332 to set the knob andhence thepiston 338 in any desired position within its range of movement.

In operation, as the control piston 338 is moved downward in the control cylinder 328, iiuid is forced into the outer cylinder chamber 383 through the control line 3|2, thus forcing the inner cylinder 298 toward the toe secti-on 42 of the foot member 36. Conversely, as ther control piston 330 is raised, the inner cylinder 298 is retracted into the primary cylinder 296, thus withdrawing it from the toe section 42. Movement ofy the inner cylinder 298 serves to adjust the point of inception of operation of the toe control unit 292.

In the control unit 292 the toe bumper comprises an arm 342 attached to one end of a torsion spring 344 arranged on a transverse rod 348 in the toe section 42, as illustrated in Fig. 13. The end of the spring 344 remote from the arm 342 presses against the toe rear face 343 and a detent 345 is mounted on the face 343 near the outer edge of the arm 342 to limit its ,rearward movement toward the toe -rod 302.

The heel control unit 350 comprises a master cylinder 352 which is rmly attached to the base 88 of the shank piece 66 behind the anklev axle 18 and also a piston 354 slidably arranged therein to move upward in response to heel pressure. The'conduit branch23| is connected to the upper end of the cylinder 352 in order to provide communication with the chamber 353 therein. This piston is mounted upon the upper end of a rod 356 which carries at its lower end a guide head 358 adapted to slide within a tubular guide 36|) mounted above the heel portion of the main foot section 48. A compression spring 362 is arranged within the guide 360 to urge the piston 354 upwards. A ring 355 press-fitted within the cylinder 352 limits the downward movement of` the piston 354. The rod 356 and the guide 360 are arranged within a bore 364 which .passes vertically throughthe heel piece |04, the heelportion 92 and the rear ankle bumper 86; andthe guide 360 is arranged on the inner end of a screw 366 wh-ich may be tadjusted vertically in the main foot section 48. A set screw 368 is providedvfor xing the adjustment` screw 386 in any desired position.

The chamber 288 in the slave cylinder 282the chamber 32.11 in the master cylinder 29a of the toe control unit 292,. thel chamber 353':V in thev master cylinder 352 ofthe heel `control unitz350,

and the interconnecting conduits 289., 290 andV 29| are substantially filled with oil or other hy' draulic fluid. It is to be understood, of course', that suit-able seals and gaskets are employed to prevent leakage of oil out of or air into anyy `of the hydraulic systems described herein'.

With the hydraulic control system described-I the check valve |58 (see Fig. 7) is rendered operative as before in response to. predetermined ball joint fleetion and heel pressure. In particular. when the ball joint 44 is flexed more thana predetermined amount, the bumper arm 342 engages th-e toe rod 302, forcing .the piston. 308 inwardly within the master cylinder 298, contracting the chamber 32| therein, thereby forcing fluid into the chamber 288 in the slavecylinder 282, expanding the latter chamber and raising the :actuator rod 284 into engagement with the check valve rod |84, rendering the check valve mechanism |58 operative, In a similar manner, when pressure exceeding a predetermined amount is applied to the heel portion 92, the ankle joint 38 isflexed, forcing the piston 354 upwardly in the second master cylinder as indicated in Fig. 12a; and also forcing fluid into the slave cylinder 282 and rendering the check valve |58 operative. When rendered operative, the check valve |58 serves to lock the knee joint 34 against further flection, as hereinabove explained.

When lemploying the adjustable toe control unit 292 described, the position of the toe rod 382 corresponding to the point of inception of operation of the hydraulic brake unit ||0 may be adjusted during use. In practice, it is found.

convenient to make this adjustment to suit the gait of the user and, in particular, to make the adjustment in accordance with the users-walkingl speed and Ealso in accordance with the slope of. the terrain over which the user is walking.

VI. Adjustment of knee joint jiecton In Figs. 1'1 to 20 inclusive, there are illustrated parts of a mechanism for permitting the knee joint to flex gradually at an adjustably controlled rate. The mechanism for controlling the rate of flection of the knee joint 34 is similar to that previously described in connection with the artificial leg of Fig.- 11, but includes an adjustable throttle valve 310 which is connected in a second passageway 312 which communicates` with the spaces |48 `and |58 on opposite sides of the knee brake piston |22, and also includes a linkage 314 which is controlled from an adjusting device 316 mounted on the upper leg member 32.

The secondrpassageway 312 is formed in part by a bore passing through a boss 318 which extends laterally from the body |60 of the check valve |58 and communicating with the lower 1portion of the check valve chamber |62 beneathv the valve seat |54. The passageway 312 continuesv through a transverse throttle valve body 380 which is secured to the lboss 318 by means of Ian apertured screw 382. A tubular member 384 which communicates, at its lower end, with the chamber 386 of the throttle valve body 380 rises upward to a cap member or 'top plate 388-through which it communicates with the upper portion of the check valve chamber |62 .above the check valve seat |64.

In this case, it is to be noted that the. upper plug tattached to the upper endpfthecheck valve body |60` is provided: with; a verticale..

throug-li-bore 390 which .forms part of the second passageway and which communicates with the expansion lchamber 392 of an accumulator 334 which is mounted at the upper end of the check valve assembly |58.

A nipple 366 extending downwardly from the accumulator body passes through the top plate 388 and threadably engages the plug |86 to hold the top plate firmly in place. The nipple 396 is provided vwith a lateral passage 398 which intersects its through-bore 399, and forms part of the second passageway 312. A follower piston 48D is urged downwardly against the force of liquid in the accumulator chamber 382 by means of a compression spring 482 arranged between the piston and a vented cap 404. The accumulator 394 serves to accommodate the expansion and contraction of fluid contained in the brake unit ||6 as a result of temperature changes and for volumetric changes therein resulting from movement of the check valve head |69.

The throttle Valve 316 is provided with a valve seat 466 at the inner end of the .valve chamber 386. A valve head 468 on the inner end of a piston 4H] works back and forth within the chamber 386 between a position engaging the valve seat Y466 and a retractedl position by virtue of the rotation of a threaded stein 4|2 passing through a threaded bore 4|3 in a cap piece 4|4 attached to the outer end of the throttle valve body 386. With this arrangement, when the check valve |58 is operative, the knee joint 34 is locked against iection as long as the throttle valve 316 remains closed, but as the throttle valve is opened, ection of the knee joint is permitted at a rate corresponding to the degree oi opening of the throttle valve.

In practice, the linkage 314 for controlling the throttle valve 318 also includes an arrangement for rendering the check valve |58 operative independently of actuation of the toe control unit or the heel control unit, so that upon subsequent opening of the throttle valve 316 the desired rate of flection of the knee joint 34 is obtained. To this end a movable arm 4|6, having its free end 4 6 located between the check valve rod |14 and the slave actuator rod 284, is pivotally attached by means of a screw 4|9 to a bracket 426 which extends forwardly from the slave cylinder body 282. In addition, a slide plate 422 is provided which has a main portion 424 provided with a short vertical slot 426 engaging a pin 428 extending laterally from the movable arm 4|6. The slide plate 422 also has an outwardly offset portion 436 having another short vertical slot 432 which rides on the boss 318 between two spacers 434 and 438.

The inner end of a divided lever 438 is pivotally attached to the upper end of the slide plate 422 and the outer end thereof engages a slot 440 in the end of a crank 442 which is firmly clamped to the outer end of the throttle valve stem 4|2. An intermediate point of the lever 438 is attached by I-means of a tension spring 446 to the end of a first transverse extension arrn 444, which extends forwardly of the slide plate 422.

A main link 448 which is piloted by a slot in the top plate 388 is pivotally attached between the branches 456 of the lever 438 and is urged by the spring 446 against the shoulder 4520i a second extension arm 454 which extends forwardly from the slide plate 422. The slide'plate 422 is raised and lowered vertically by means of a stii Wire 456 which extends through a asiatica housing 458, which passes through the hole 324 in the lower leg member 3!)v (see Fig. 11) to the adjusting device 316. The lower and upper ends of the housing 458 respectively are firmly secured to the upper and lower limb members by means of suitable clamps 466 and 462.

The adjusting device 316 'which is used for operating the linkage 314 includes a terminal arm 464 attached to the uppermost end of the wire 456 and guided vertically in suitable guides 466 formed in a plate 468 attached to the upper leg member 32. The terminal arm 464 is raised and lowered by means of rollers 410 pivoted thereon, which rollers engage the cam surface of a snail cam 412 rotated by means of an adjusting knob 414 which may be adjustably set by a ball and spring detent, as previously described. It is to be noted that the rollers 410 are mounted above the snail cam l412 and are held rmly against the cam surface by the ten sion applied to the wire 4.56 by the coil spring 446. The shaft 416 joining the cam 412 and the knob 414 extends through a vertical slot 4`l8 in the terminal arm 464, and the cam 412 is preferably formed of two similar parts which engage rollers 416 on opposite sides of the terminal arm.

In the normal course of walking with an artiiicial leg including this system, the throttle valve 310 is held closed by the coil spring 446; and the slide plate 422 is held in its lowermost position by the springs |11 and |18, which float the valve |69 (see Fig. 7) and the weights of the various parts of the linkage 314. During the use of the artiiicial leg, the actuator rod 234 is raised and lowered in response to predetermined action of the artiiicial foot, as previously described. As the actuator rod 284 is raised and lowered, it moves the check valve rod |14 up and down through the intermediary action of the outer end 4|8 of the movable arm 4|6. Such movement or" the arm 4|6 is not restricted materially by .virtue of the fact that the pin 428 is free to move between suitable limits in the lower slot 426 in the slide plate 422. Thus, during the normal operation of walking, the hydraulic brake unit of this articial leg operates substantially identically with those hereinabove described. Y

If at any time it is desired to flex the knee while the check valve |58 is in its operative condition by virtue of operation by the slave device 288, the throttle valve may be opened to any desired degree by turning the knob 414 in the adjusting device 316. As this knob is turned, the snail cam 412 rotates, raising the terminal arm 464 a corresponding amount and thus raising the main link 448. As the main link 448 is raised, the lever 438 and the slide plate 422 are carried upward until the lower end of the upper slot 432 engages the boss 318. At that point, further upward movement of the slide plate 422 is discontinued and further raising of the main link 448 causes the lever 438 to rotate on its pivot against the force of the coil spring 446. During this pivotal movement of the lever 438, the outer end thereof turns the crankV 442 and thus withdraws the throttle valve head 408 from its seat 466. When the throttle valve 310V is thus opened, assuming the check valve |58 is still operative, uid passes therethrough from the space |50 beneath the Vbrake piston |22 to the space |48 above the brake piston, permitting the knee joint V34 to iiex. The rate at which the knee joint flexes depends on the hydraulic resi/stance in the secv ond passageway. asy determinedbv thev degree of opening of the throttle valve 3,10. Upon returning the control knob 414i to its home position, lection of the kneejoint; 3 4 is discontinued, provided, of course,v that the check Va1ve l58 remains operative. During any of this action,V it is, of course, possible for the user of the artificial leg to straighten the knee joint by applying the proper force to the artificial leg.

If for any reason it is desiredv to flex the knee joint at some predetermined rate. even. though the check valve is not already in Van operative condition as a result of action of either the toe control unit or the heel control unit; the control knob 414 of the adiustnedevee 315 manioulated as before. But, in this case, as slide plate 422 is raised,.it turns the movable alfril 4.|, loreing theV check valve rod |14 upward and L r c` end l a r ing the check valve operative before thelever 438 is turned to open the throttle Vele .32.79.1.31 this operation, the closing of the hekyalve |58 rst 4looks the knee joint-34 and, .thee die check valve is. bypassed by the opening or the throttle valve 310. The degree of opening of the throttle valve determines the rate of knee joint flection. v

vii. Mechanical adjustment of toe" oo'vitoz tot:

vrn' Figs, 20y toj24 inclusive; there are illustrated parts of an artificial leg'v which', include a rnechanical arrangement for adjusting the pointof inception of the toe' control unit.A v'Vvlrile'this arrangement maybe adapted'drectly to thearti'- flcial leg illustrated in Fig. 1 It is described herein as applied to4 such' an art' les modified' by the" incorporation of the adjusting rnjecl'l'- anisrn just described. Thev foot rnernber 36' of this articial leg employs; a ball' j oint 44 comprising twol hinged pIateS'SD and 492 which are respectively b'olted' to the' toe section .442" and themain foot portion 4.0i A. torsion .Splng 94 enf-loting the hinge shaft 41362, which 'hinges' the two plates Vll9`0a'n'd 4912, normally urgesjthminto alignment and resists llectionK of the baljl jointy M fritoy toe control unit cc' tir-s artificial' foot is of similar construction to that previously described in r1ig.l 12'. However,` in this case the mas- "t'e'r cylinder 502 isl mounted inV sliding engagement with a guideframe tot vvl'iicnA is nr ly bolted to the rear ball joint plate 4:92. I naster cylinder 502 is urged into a forward' position by a compression; sonne 506i errengedheiween a 'guide flange' 508 formed in the cylinder and the4 rearend-plate `510 of tl'l'e`guide frame' 504. A pair' or stub rods mi extending laterally trom the master cylinder 502 ride in slots 5 l41in the side Walls 516 of the -guide frame 504'. The free ends" of th two' laterally spacedarrns 5-"I8j of a yoke member are pivotally` attached to the stub rods 5l2' on opposite sides" of the' g-uide frame 504.

VThev cross arm 520 of thel yoke member is attached`- to a stiff wire 522 whichv leadsto the adjusting device 316: mounted on the upper limb member and which serves' as yai control line. The wife 5212 is enclosed in' a housing 524- which is secured to the' main foot section 60 by means of a fitting 52-6" and isV secured to the upper limb member by a clamp 528 attached to' a'V side plate 530 in the adjusting device 316i. A- compression spring 532', arranged between `the yoke cross arm 520A and the fitting V526;.aids in forcing .the master cylinder 502 into its forward position.

The master .cylinderei iS' .drawn rearwardly in the guide frame 504n by raising a lever 534 pivoted on the side plate 530 and attached to the uppermost end of thewire 5 22'. A knulfled knob 536 at theouternlost end of a screw 538 pass-1 ing through an arcuate slot 540v in the side plate 530 and into a threaded bore' at the outermost end of the lever 534 is used fory locking the lever 534 any desired position on the side plate'. A limit stop screvv 542, having a k'r'iu'rledhead 544, may be adjustably positioned in the slot 540' at any desired position to' limit the upward move'- nientof tno lever' 534. By rainjg and `lowering tho' lover 534, the mastr'oyllndor 502 is moved backward and forward in' the guide' frame 504 and may be locked at any desired position therein to establish' the point ofincoptiorl of operation of the toe @beta1 uniti 0,- j

A toe rod 46 exten lg through the forward e'nd of the Yin'ar'iizer'- cylinder 502 Ais forced forwardly therei by a c orfrip ess'iol'l' spring'- 548 which pushes on a piston 55u' attached to' the toe' iod 546 endelldeblv overleed in the erleidet. A stub shaft5'52 extending rearwardly of the' .pistn 55u serves to limit the rearward' movement of trie' piston in tho master cyliilder to2, A cross slot 554 in' the end or tno' shaft s tz provides communication bottoni the cylinder chamber 55s and the passage 55s iii the tallplooo 515.11 which communicates withl the conduit branch 29o'. To reduce wear on' the toe rod, the control element mounted on' the toe Section 4j2 comprises' on antiiriction roller' sez which rotates o nj d shaft 564 totvveentwo ses extending upwardly from theforwardball joint plate 490.

The operation of the t' control unit 500 is substantially the same as that previously de'- sc'ribed in connectionwith Figs. 1 1 and 12, the main difference being in thesub'stitution of a mechanical arrangemr'it'mr a hydraulic arrangementfr adjusting the point of inception of operation of the control It is to' be noted, however, in this case the springs sus. 532, and 5.4'8 force master cylinder 502 into its most forward positioncorresponding to ball joint flection required foi' actuation, in' the event that part of the adjusting' meonanlam suoli as the wire should be broken.

VIII; Ellectr'iolly controlled knee brake In Figs. 2 5 to 28 inclusive vthereis illustrated an electrically controlled artificial leg employing the principles of my invention. In this case, the slave unit A510, which is mounted on the hydraulic brake unit lll),v comprises a sclenoid 512 which forces the actuator rod 514 upward to render the check valve |58 operative only when the solenoid is electrically energized.

The battery 592 for energizing the solenoid 512 is preferably mounted in a pocket 594 which is attached to the upper leg member y32. The sole- @tiene .of ,o scatto. ,one sottolineo- 1 rearwardly @id .e oompre'sitior `stllljg' 608, er'- rangel between .the toe bumper 60A and the inner end of an adjusting screw El@ which carries pins @E2 which project outwardly in longitudinal slots 5M in the sleeve. The adjusting screw 5H] passes through a threaded block 525 inserted into a recess in the top of the toe section i2 and is employed to adjust the position of the toe bumper 554 thereon. The toe bumper 5M moves along a line which passes radially through the contact closing button EIB mounted on the forward side of the microswitch 555. It is to be noted that the compression spring 658 serves to compensate for excess iiection of the ball joint lid once the microswitch 555 is closed.

Ihe heel control unit 652 includes a push rod 525 which is guided by a collar 62| in a vertical bore 522 in the heel portion 92 of the main foot section llt. The push rod 620 is normally urged into its downward position by means of a compression spring Z arranged between a head 626 attached to its lower end and an inwardly extending flange 628 formed in the upper end of a tube 63D suitably secured within the bore G22. The flange 628 of the tube 630 also serves as a stop to limit the downward movement of the push rod 62B by engaging the collar 52E. In response to heel pressure, the push rod 625 is forced upwardly into engagement with a button 632 of the heel microswitch 558. The adjustment of the point of inception of operation of this micros-witch 598 is accomplished by means of an adjusting screw 634 which works against a rearwardly extending leaf spring 635 which supports the microswitch 593 on the main foot section 45.

The solenoid 572 is mounted in a recess 5715 in a cup-shaped member 518 which registers the actuator rod 5M with the valve rod |74, as hereinabove explained in connection with Fig. '7. A.

sleeve 519 composed of non-magnetic material is arranged with the solenoid and a screw cap 5t@ serves to hold the solenoid and sleeve in place.

A cylindrical core 582 composed of magnetic material is secured to the lowermost end of the actuator rod 514 and the actuator rod is piloted by a bore 584 in the cap and a bore 586 in the bottom wall forming the recess 575. A compression spring 558 arranged between the cap 585 and the core 582 serves to urge the actuator rod 51d downward away from the check valve |53. With this arrangement, when the solenoid 5'i2 is energized, the magnetic core 582 is drawn upwardly therein against the force of the spring 58S, causing the actuator rod 514 to engage the valve rod |14. By applying sufficient current to the solenoid the check valve is rendered operative.

IX. Summary From the foregoing description of my invention, it is apparent that I have provided a knee lock mechanism for artificial legs which oifers many advantages over those available heretofore. Looked at broadly, this knee lock mechanism includes a knee brake unit which is actuated in response either to toe joint flection or to heel pressure. While the particular knee brake unit which I have illustrated is of the hydraulic type, it is to be understood that other types of brake units may be employed, even brake units which operate on mechanical or electrical principles. Furthermore, it is to be understood that the knee brake mechanism may under some circumstances be actuated in other ways without departing from the principles underlying my invention.

While the particular means which I have illustrated to actuate the knee brake unit includes toe control and heel control units of specific mechamcal, hydraulic, and electrical forms, it is also to be understood that other forms of control units may be read-ily devised b y those skilled in :the art without departing from the principles underlying my invention. In a like manner it is to be understood that many changes may be made in other features of my invention which have been described, su-ch as the devices which are employed for adjusting the toe control and heel control units and the device for adjustably flexing the knee joint, without departing from the principles of my invention.

Accordingly, since many modifications and chang-es can be made in the construction and arrangement of the parts of my invention by those skilled in the art without departing from the true spirit and scope of my invention, it is to be understood that my invention is not to be limited to the speciiic forms illustrated and described but is to be construed broadly inthe light of the appended claims. 1

I claim as my invention: v

1. An artificial leg comprising upper and lower leg members pivotally attached by a knee joint, a braking device comprising a pair Iof cooperating brake members respectively connected to said upper and lower leg members, said brake members being adapted upon operation to resist flection of said knee joint, an articulated foot member having a main section pivotally attached to the lower leg member and a toe section .pivotally attached to said main section by a ball joint, iirst and second cylinders mounted respectively at the forward and rear ends of said main foot section, common hydraulic conduit means communicating with the interiors of said cylinders, means controlled by movement of fluid in said hydraulic conduit means for operating said braking device, a iirst piston slideably arranged in said first cylinder and adapted to slide therein upon iiection of said ball joint beyond a predetermined amount whereby flection of said knee joint is resisted, and a second piston slideably arranged in said second cylinder adapted to slide therein upon application of pressure exceeding a predetermined amount to the heel portion of said main foot section whereby iection of said knee joint is resisted.

2. An artificial leg comprising upper and lower leg members pivotally attached by a knee joint, a braking device comprising a hydraulic cylinder and a piston working therein connected between said upper and lower leg members, a check valve mechanism arranged in a passageway interconnecting spaces in said cylinder on opposite sides of said piston, said check valve mechanism being operative to block the flow of fluid in one direction in said passageway whereby fiection of said knee joint is prevented without interfering with extension or said knee joint, an articulated foot member having a main section pivota-lly attached to the lower leg member and a toe section pivotally attached to sai-d main section by a ball joint, a iirst control device adapted for actuation upon iiection of said ball joint beyond a predetermined amount, a second control device adapted for actuation upon application of pressure exceeding a predetermined amount to the heel portion of said main foot section, and common means controlled by actuation of either of said control devices for rendering said check valve mechanism operative whereby said knee joint is locked ac-iaeca 21 against flection upon occurence of such ball joint iiection or such heel pressure.

3. An artificial leg comprising upper and lower leg members pivotally attached by a knee joint, a braking device comprising a pair of cooperating brake members respectively connected to said upper and lower leg members, said Vbraking device being adapted upon operation to resist flection of said knee joint, an articulated foot member havingv a main section pivotally attached `to said lower leg member and a toe section pivotally attached to said main section by a ball joint, actuating means located adjacent the ball joint and controlled by flection of said ball joint beyond a predetermined amount for operating said braking device whereby lection of said knee joint is resisted, sai-d actuating means comprises an actuating member mounted on the main foot section, said actuating member being arranged to contact .part of said toe section upon flection of said ball joint beyond a predetermined amount whereby said braking device is vopera-ted, said articial leg also comprising a carriage member movably mounted on said main foot section and carrying said actuating member, a control line connected at its lower end to said carriage member and having its upper end mounted upon the upper leg member, and an adjusting -device at said upper end for adjustably transmitting a force to said carriage member through said control line to adjust the position of said actuating member on said main foot section whereby the degree of ball joint ection corresponding to inception of operation of said braking device is varied.

4. An artificial leg as deiined in claim 3 wherein said control line is in the form vof a stiff wire arranged in a flexible tubular housing which is led upward from said foot member through the lower leg member to a position on the outside of said upper leg member, the lower end of said tubular housing being iirmly attached at the lower end of said main foot section and the upper end thereof being rmly attached to said upper leg portion, and said adjusting device including means for moving said stiff wire lengthwise in lsaid tubular housing for effecting the desired movement of the carriage member.

5. An artificial leg as dened in claim 4 comprising a spring arranged to force said actuating 'member toward a position in which inception of brake operation occurs at a relatively low degree of ball joint flection.

6. An articial leg comprising upper and lower leg members pivotally attached by a knee joint, a braking device comprising a pair of cooperating brake members respectively connected to said upper and lower leg members, said braking device being adapted upon operation to 'resist flection of said knee joint, an articulated foot member having a main section pivotally attached to the lowerleg member and a toe section pivotally 'iiectionbeyond a predetermined amount determined by the position of said secondary cylinder relative to said main foot section, and means including a second hydraulic line communicating with the interior of said secondary cylinder for operating said brake device whereby iiection of the knee joint is resisted when the ball joint is flexed more than said predetermined amount.

'7. An artificial leg as dened in claim 6 wherein the upper end of said rst hydraulic line ter-` minates adjacent the hip position of said upperl leg member, said artificial leg also comprising a plunger slideably arranged in the upper end oi' said hydraulic line, and means for manually adjusting the position of said plunger in said hydraulic line for effecting the desired adjustment ci? the position of said secondary cylinder.

8. An artificial leg comprising upper and lower leg members pivotally attached by a knee joint, a braking device comprising -a pair of cooperating brake members connected to said upper and lower leg members respectively, said brake members being adapted upon operation to resist flection of said knee joint, a foot member pivot'- ally attached to the lower leg member, a push rod passing upwardly through the point oi pivoting of said foot member on said lower leg member, said push rod terminating adjacent the ankle and means controlled by upward pressure on the heel portion of saidr foot member for urging said push rod upwardly, and means inciuding a second rod engaging said push rod adjacent the ankle controlled by upward movement of said push rod for operating said braking device whereby lection of said knee joint is resisted.

9. An articial leg comprising upper and lower leg members pivotally attached by a knee joint, a braking device comprising a, pair of cooperating brake members connected to said upper and lower leg members respectively, said brake members being adapted upon operation to resist Flection of said knee joint and upon release to permit f1ection,-a foot member pivotally attached to the lower leg member by an ankle joint, a movable foot portion located in the lower part of said main foot member and movable relative to said main foo-t member, means resiliently forcing said foot portion downward relative to said main foot member, a pilot element mounted on said foot member and rotatable therewith, a mechanical element extending through said pilot element from said main foot member to said lower leg member through the axis of said ankle jointand movable upwardly and downwardly therein and means connected to said mechanical element adjacent the ankle for operating and releasing said braking members, means controlled by upward movement of said foot portion relative to said main foot member for moving said mechanical' element upwardly through said pilot element, whereby said iiection of said knee joint is resisted in accordance with said relative movement of said foot portion independently of the angular position of said main foot member relative to said lower leg member.

10. In an articial leg, the combination which comprises upper and lower leg members pivotally attached by a knee joint, a braking device comprising a hydraulic cylinder and a piston working therein connected between said upper and -lower leg members, a check valve arranged in a first passageway interconnecting spaces in said cylinder on opposite sides of said piston, said check valve being operative to block the flo-w of uid in one direction in said first passageway whereby iiection lofrsaid knee joint is prevented without interfering with extension of said rknee joint, a

throttle valve arranged in a second passageway interconnecting the spaces in said cylinder on opposite sides of said piston, and control means including an adjusting member mounted above said knee joint for adjustably opening said throttle valve while said articial leg is in use whereby fluid is permitted to flow past said check valve at a variably controlled rate while said check valve is operative so as to control the rate of flection of said knee joint.

l1. An artificial leg as deiined Iin claim 10 wherein said adjusting member comprises a pivoted handle at the hip position of the upper leg member.

12. An articial leg comprising upper and lower leg members pivotally attached by a knee joint, a braking device comprisingr a hydraulic cylinder and a piston working therein connected between said upper and lower leg members, a check valve arranged in a first passageway interconnecting spaces in said cylinder on opposite sides of said piston, said check valve being adapted to be rendered operative to block the flow of uid in one direction in said first passageway whereby flection of said knee joint may be prevented without interfering with extension of said knee joint, means controlled by predetermined movement of part of said artificial leg for rendering said check valve operative whereby said knee joint is locked against flection, a throttle valve arranged in a second passageway interconnecting the spaces in said cylinder on opposite sides of said piston, and control means including an adjusting member mounted above said knee joint for adjustably opening said throttle valve whereby uid is permitted to iiow past said check valve at a variably controlled rate while said check valve is operative so as to control the rate of fiection of said knee joint.

13. An articial leg comprising upper and lower leg members pivotally attached by a knee joint, a braking device comprising a hydraulic cylinder and a piston working therein connected between said upper and lower leg members, a check valve mechanism arranged in a rst passageway interconnecting spaces in said cylinder on opposite sides of said piston, said check valve mechanism being adapted to be rendered operative to block the ow of iluid in one direction in said first passageway whereby lection of said knee joint may be prevented without interfering with extention of said knee joint, a throttle valve arranged in a second passageway interconnecting the spaces in said cylinder on opposite sides or" said piston whereby fluid may be flowed past said check valve at a variably controlled rate while said check valve is operative, and common control means for rendering said check valve operative and for then adjusting the opening of said throttle valve whereby the rate of ilection of said knee joint is varied.

14. An articial leg comprising upper and lower leg members pivotally attached by a knee joint, a braking device comprising a hydraulic cylinder and a piston working therein connected between said upper and lower leg members, a check valve arranged in a iirst passageway interconnecting spaces in said cylinder on opposite sides of said piston, said check valve being operative to block the flow of fluid in one direction in said rst passageway whereby lection of said knee joint may be prevented without interfering with extension of said knee joint, a throttle valve arranged in a second passageway interconnecting the spaces in said cylinder on opposite sides of said piston whereby iluid may be flowed past said check valve at a controlled rate while said check valve is operative, a control handle having an inoperative position and a range of operative positions, common means controlled by predetermined movement of a part of said artificial leg and by movement of said control handle from said inoperative position into said range of 0perative positions for rendering said check valve operative whereby said knee joint is locked against iiection, and means controlled by further movement of said control handle in said range of operative positions for adjusting the opening of said throttle valve whereby the rate of flection of said knee joint is varied.

15. An articial leg comprising upper and lower leg members pivotally attached by a knee joint, a cylinder body and a piston working therein connected between said upper and lower leg members, a check valve housing mounted on said cylinder body and provided with a passageway interconnecting spaces in said cylinder body on opposite sides of said piston and also provided with a valve seat in said passageway, a check valve head guided in said passageway, a check valve shaft extending through said check valve housing, means operatively associated with said valve head for normally maintaining said check valve head in a position withdrawn from said valve seat, and means controlled by movement of a part of said artificial leg for moving said valve shaft to force said valve head against said valve seat whereby the iiow of fluid is blocked in one direction in said passageway thereby locking said knee joint against flection.

16. An artificial leg as dened m claim l5, comprising spring means arranged between said valve shaft and said valve head for oating said valve head in said passageway whereby the flow of fluid in a direct-ion opposite to said one direction is facilitated to permit knee joint flection.

17. An articial leg comprising upper and lower leg members pivotally attached by a knee joint, a cylinder body and a piston working therein connected between said upper and lower leg members, a check valve housing mounted on said cylinder body and provided with a passageway interconnecting spaces in said cylinder body on opposite sides of said piston and also provided with a valve seat in said passageway, a check valve head guided in said passageway, a check valve rod extending through said check valve housing, means for normally urging said check valve head into a position withdrawn from said valve seat, actuator means mounted on said cylinder body and operatively associated with said valve rod for moving said valve head into and out of engagement with said valve seat, and means controlled by a predetermined movement of a part of said artificial leg for operating said actuator means to force Said valve head against said valve seat, whereby the ow of fluid is blocked in one direction in said passageway thereby locking said knee joint against ection. 18. An artificial leg comprising upper and lower leg members pivotally attached by a knee joint, a brake cylinder body and a brake piston working therein connected between said upper and lower leg members, a check valve housing mounted on said brake cylinder body and provided with a passageway interconnecting spaces in said brake cylinder body on opposite sides of said piston and also provided with a valve seat in said passageway, a check valve head guided in said passageway, a check valve rod extending 25 through said check valve housing, means for normally urging said check valve head into a position withdrawn from said valve seat, a slave cylindervmounted on said-brake cylinder body, a slave'piston working in said slave cylinder, anactuator 'rod connected to said slave ypiston and operatively associated with said valve rod for moving said valve head into and out of engagement with said valve seat, a master cylinder mounted on said artificial leg and communicating with said slave cylinder by means of a hydraulic line, a master piston working in said master cylinder and operative to displace fluid therein in response to predetermined movement of a part of said artificial leg`whereby said ac- Y tuator rod isl moved to force 'said valve head against said valve seat whereby the flow of fluid is blocked in'one direction in said passageway thereby locking said knee joint against flec'tin.

19. An artificial leg comprising upper and lower leg members pivotally attached by a knee joint, a cylinder body and a piston lworking therein connected between said upper and lower leg members, a check valve housing mounted on said cylinder body and provided with a first passageway interconnecting spaces in said cylinder body on opposite sides of said piston and also provided with a valve seat in said passageway, a check valve head guided in said passageway, a check valve shaft extending through said check valve housing, means for normally urging said check valve head into a position withdrawn from said valve seat, an actuator rod aligned with said valve stem, a throttle valve arranged in a second passageway interconnecting the spaces in said cylinder on opposite sides of said piston, a movable arm arranged between said actuator rod and said valve stem, means controlled by predetermined movement of a part of said artificial leg for forcing said actuator rod against said floating arm and the oating arm in turn against said valve shaft for forcing said valve head against said valve seat, means for forcing said movable arm against said valve shaft to force said valve head against said valveseat independently of said predetermined movement, said check valve being operative when said valve head is seated to block the flow of fluid in one direction in said first passageway thereby locking said knee joint against flection, and means for adjustably opening said throttle valve while said check valve is operative whereby fluid flows past said check valve at a controlled rate to control the rate of flection of said knee joint.

20. An artificial leg comprising upper and lower leg members pivotally attached by a knee joint, a cylinder body and a piston working therein connected between said upper and lower leg members, a check valve housing mounted on said cylinder body and provided with a first passageway interconnecting spaces in said cylinder body on opposite sides of said piston and also provided with a valve seat intermediate the ends of said passageway, a check valve head guided in said passageway, a check valve shaft extending through said check valve housing, means for normally urging said check valve head into a position withdrawn from said valve seat, a movable arm operatively associated with said valve shaft, a throttle valve arranged in a second passageway interconnecting the Vspaces in said cylinder on opposite sides of said piston, control means for moving said arm relative to said valve shaft wherebyV said valve head is forced against said valve seat thereby blocking the now of fluid in 126 one direction in saidfrst passageway and then adjustably opening said throttle valve whereby fluid flows in an opposite direction in said secondl passageway at a controlled rate therebylcontrolling the rate of flection of said knee joint.

2l. In a locking device for an artificial limb comprising two members pivotally attached at a joint, a valve body adapted for 'pivotal attachment to oneof said limb membersgsaid valve body comprising a working cylinder, a working piston slideably `arranged in said working cylinder and guided therein by a rod passing through said valve body, said rod being adapted for pivotal attachment to the other limb member, a passageway arranged in said valve body and communicating with said working cylinder on opposite sides of said working piston, a valve seat arranged in said passageway, a check valve head movable in said passageway between an operative position in engagement with said valve seat and a withdrawn position out of engagement with said valve seat, a valve shaft pro,- jecting through said valve body and operatively associated with said valve head, spring means normally urging said valve head into said withdrawn position and for urging said valve shaft into a corresponding position, and means responsive to predetermined movement of said artiiicial limb for moving said valve shaft against the force of said spring means to force said valve head into operative position.

22. In a locking device for an artificial limb comprising two members pivotally attached at a joint, a valve body adapted for pivotal attachment to one of said limb members, said valve body comprising a working cylinder, a working piston slideably arranged in said working cylinder and guided therein by a rod passing through said valve body, said rod being adapted for pivotal attachment to the other limb member, a passageway arranged in said valve body and communicating with said working cylinder on opposite sides of said working piston, a valve seat arranged in said passageway, a check valve head carried by a valve piece which is slideably arranged in a guide bore passing through said valve body, a valve shaft slideably arranged in said guide bore, a first spring passing through said valve seat arranged between said valve head and said valve body, a second spring arranged between said valve piece and said valve shaft,` said springs cooperating to urge said valve head into said withdrawn position and saidvalve shaft into a corresponding position, and means respon- -sive to predetermined movement of said artificial limb for moving said valve shaft against the forces of said springs to force said valve head into operative position.

23. An artificial foot comprising a main foot section adapted for support on an artificial leg, a toe section pivotally attached to said main foot section by a ball joint, a control cylinder mounted on said main foot section and adapted for connection to a control conduit, and a piston slideably arranged in said cylinder and carrying a piston rod adapted to be engaged by said toe section upon flection of said ball joint.

24. An artificial foot as defined in claim 23, comprising a guide mounted on said main foot portion, said control cylinder being slidealoly arranged on said guide, and a spring urging said cylinder into a forward position on said guide.

25. An artificial foot as defined in claim 23, comprising a second cylinder operatively enclosing said control cylinder whereby said control 27 cylinder acts as a piston therein, said second cylinder including a connection for establishing communication of the working space therein with a conduit.

26. An artificial foot as defined in claim 25, including a spring for urging said control cylinder in a direction to reduce the volume of said working space.

27. An articial foot as dened in cla-im 23, comprising an antifriction roller mounted on said toe section for operatively engaging said piston rod during flection of said ball joint.

KARL C. VESPER.

REFERENCES CITED The following references are of record in the file of this patent:

Number Number UNITED STATES PATENT Y Name Date Kolbe Jan. 7, 1890 Kelly Apr. 11, 1911 Michajlov Feb. 13, 1917 Knudsen Apr. 19, 1921 Sprouls Feb. 23, 1937 Filippi Dec. 15, 1942 Eberle et al June 1, 1948 FOREIGN PATENTS Country Date Great Britain Apr. 1, 1920 Switzerland Aug. 16, 1938 Great Britain Sept. 13, 1923 Germany May 13, 1915 France Dec. 21, 1920 France Apr. 19, 1921 France Oct. 12, 1921 

